/*

  * #%L

  * GetLastError.java - mongodb-async-driver - Allanbank Consulting, Inc.

  * %%

  * Copyright (C) 2011 - 2014 Allanbank Consulting, Inc.

  * %%

  * Licensed under the Apache License, Version 2.0 (the "License");

  * you may not use this file except in compliance with the License.

  * You may obtain a copy of the License at

  * 

  *      http://www.apache.org/licenses/LICENSE-2.0

  * 

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  * #L%

  */

 package com.allanbank.mongodb.client.message;

 import java.io.StringWriter;

 import com.allanbank.mongodb.Durability;

 import com.allanbank.mongodb.ReadPreference;

 import com.allanbank.mongodb.bson.Document;

 import com.allanbank.mongodb.bson.builder.BuilderFactory;

 import com.allanbank.mongodb.bson.builder.DocumentBuilder;

 import com.allanbank.mongodb.bson.element.JsonSerializationVisitor;

 import com.allanbank.mongodb.client.connection.Connection;

 /**

  * Provides a convenient mechanism for creating a <a href=

  * "http://www.mongodb.org/display/DOCS/getLastError+Command" >getlasterror</a>

  * command.

  * <p>

  * This is a helper class for retrieving the results of {@link Delete},

  * {@link Insert}, and {@link Update} commands. Get last error is not a part of

  * the standard wire protocol but is provided here due to the frequency of

  * usage.

  * </p>

  * 

  * @api.no This class is <b>NOT</b> part of the drivers API. This class may be

  *         mutated in incompatible ways between any two releases of the driver.

  * @copyright 2011-2013, Allanbank Consulting, Inc., All Rights Reserved

  */

 public class GetLastError extends Query {

     /**

      * Creates the query document for the getlasterror command.

      * 

      * @param fsync

      *            If true the command waits for an fsync of the data to have

      *            completed.

      * @param waitForJournal

      *            If true the command waits for the preceding command to have

      *            been written to the journal.

      * @param w

      *            The replication factor to wait for.

      * @param wtimeout

      *            The amount of time (in milliseconds) to wait for the write to

      *            finish.

      * @return The command's query document.

      */

     private static Document createQuery(final boolean fsync,

             final boolean waitForJournal, final int w, final int wtimeout) {

         final DocumentBuilder builder = BuilderFactory.start();

         builder.addInteger("getlasterror", 1);

         if (waitForJournal) {

             builder.addBoolean("j", waitForJournal);

         }

         if (fsync) {

             builder.addBoolean("fsync", fsync);

         }

         if (w >= 1) {

             builder.addInteger("w", w);

         }

         if (wtimeout > 0) {

             builder.addInteger("wtimeout", wtimeout);

         }

         return builder.build();

     }

     /**

      * Create a new GetLastError.

      * 

      * @param dbName

      *            The name of the database.

      * @param fsync

      *            If true the command waits for an fsync of the data to have

      *            completed.

      * @param waitForJournal

      *            If true the command waits for the preceding command to have

      *            been written to the journal.

      * @param w

      *            The replication factor to wait for.

      * @param wtimeout

      *            The amount of time (in milliseconds) to wait for the write to

      *            finish.

      */

     public GetLastError(final String dbName, final boolean fsync,

             final boolean waitForJournal, final int w, final int wtimeout) {

         super(dbName, Connection.COMMAND_COLLECTION, createQuery(fsync,

                 waitForJournal, w, wtimeout), /* fields= */null,

         /* batchSize= */1, /* limit= */1, /* numberToSkip= */0,

         /* tailable= */false, ReadPreference.PRIMARY,

         /* noCursorTimeout= */false, /* awaitData= */false,

         /* exhaust= */false, /* partial= */false);

     }

     /**

      * Create a new GetLastError.

      * 

      * @param dbName

      *            The name of the database.

      * @param durability

      *            The Durability requested.

      */

     public GetLastError(final String dbName, final Durability durability) {

         super(dbName, Connection.COMMAND_COLLECTION, durability.asDocument(),

         /* fields= */null, /* batchSize= */1, /* limit= */1,

         /* numberToSkip= */0, /* tailable= */false, ReadPreference.PRIMARY,

         /* noCursorTimeout= */false, /* awaitData= */false,

         /* exhaust= */false, /* partial= */false);

     }

     /**

      * {@inheritDoc}

      * <p>

      * Overridden to returns the getLastError on a single line.

      * </p>

      */

     @Override

     public String toString() {

         final StringWriter sink = new StringWriter();

         final JsonSerializationVisitor visitor = new JsonSerializationVisitor(

                 sink, true);

         getQuery().accept(visitor);

         return sink.toString();

     }

 }